Medical article having fluid control film

ABSTRACT

The present invention provides medical articles having a fluid control film component which comprise a sheet having microchannels that permit directional flow of a liquid. Articles incorporating the fluid control film include: wound dressings, wound drains, tympanostomy fluid wicks, intravenous access site dressings, drug delivery dressings, and sweat collection patches.

FIELD OF THE INVENTION

[0001] This invention relates to articles that have the capability tocontrol or transport fluids, especially biological fluids. In oneembodiment this invention relates to medical wound dressings and drainsand intravenous access site dressings.

BACKGROUND OF THE INVENTION

[0002] The control and/or transport of biological fluids poses manyproblems at different stages in treatment or diagnosis processes. Duringsurgery, steps are undertaken in an effort to control and/or transportthe fluids that result from the surgery. In some instances these fluidsare needed to be recycled back to the patient. For example, vital bloodlost from the patient may be returned in emergency situations. In otherinstances fluids must be controlled so that an aseptic and safeoperating room environment is maintained. It is often times desired, forexample, to avoid spillage of fluids onto the operating room floor whereit would create an unsafe situation and mess. After surgery, the need tocontrol and/or transport fluids remains. For example, wound exudate canpose problems in the treatment and care of the wound site and needs tobe handled. Also, the delivery of fluid medicaments to a wound site canpresent challenges.

[0003] Several surgical drapes and pouches have been designed in anattempt to control fluids generated during surgery. Many of thesedevices utilize absorbent padding or plastic pouches to collect thefluid. In many situations, however, there does not exist enough room atthe site where the fluid is emanating from to adequately control thefluid.

[0004] Suction tubes, optionally connected to a central vacuum line orremote vacuum source, may also be employed to collect fluids from awound site. These tubes have a significant number of limitations thatinhibit the desired management of the fluid. For example, post operativewound drain tubes create significant patient discomfort and can be asource of infection. Furthermore, many wounds require multiple draintubes.

[0005] In the treatment of many wounds it is beneficial to keep thewound moist while removing excess exudate. This environment provides anoptimum wound healing environment, reduces pain, and provides anenvironment for autolytic debridement and re-epilethlialization. Excessfluid, however, can lead to problems such as maceration (skin breakdown)and microbial infection of the wound site. For this reason, many wounddressings are sometimes designed to have absorbent pads and/or highmoisture vapor transmission rates (hereinafter “MVTR”), i.e. the excessfluid is allowed to transmit or evaporate through the wound dressing.

[0006] Fluid can be a particular problem when dealing with highlyexuding wounds, IV sites, as well as sites for gastric (G), jejunostomy(J) and nasal gastric (NG) tubes. For example, many commerciallyavailable intravenous access site dressings (hereinafter “I.V.Dressings”) do not have sufficient MVTR to permit rapid evaporation ofmoisture through the dressing. Consequently, in some instances this canresult in fluid pockets forming beneath the dressing around the puncturesite. This fluid can result in one or more problems such as “bandagelift” (which reduces the ability of the bandage to secure the IV line tothe skin), skin maceration, or bacterial infection.

[0007] A stated advantage to certain of these dressings is transparencyof part or all of the dressing. This allows for direct visualobservation of the wound healing progress. For example, thin filmadhesive coated dressing having a site revealing “window” surrounded byan absorbent such as a hydrocolloid have been tried. Unfortunately,however, these dressings require that the “window” be relatively smallto ensure that the fluid be in sufficient direct contact with theabsorbent to prevent fluid build up. Even so, these small dressings maynot absorb fluid rapidly enough to prevent fluid build up around the IVpuncture site.

[0008] Alternatively, attempts have been made to place a gauze absorbentor an “island dressing” (i.e., a dressing having an “island” ofabsorbent fabric or hydrophilic foam contained therein) directly overthe wound. Island dressings are able rapidly to absorb fairly highamounts of wound exudate and, therefore, are useful for highly exudingwounds. Unfortunately, however, the presence of the absorbent directlyover the wound prevents visual observation of wound healing. Finally,certain transparent hydrocolloid dressings are also available thatabsorb the fluid into a polymeric matrix. These dressings can absorblarge volumes of fluid but generally the absorption is not very rapidand hydrocolloids tend to break down in the wound.

[0009] Drug delivery dressings have been developed that contain areservoir of a suitable medicament. The reservoir is placed in contactwith the skin and the medicament is allowed or assisted to permeate theskin. Unfortunately, the amount of drug contained within the dressing islimited for a particular size of dressing and these dressings do nothave a capability to be recharged from a remote reservoir. Many of thesedressings are not suitable for application over open wounds. Forexample, many transdermal drug delivery devices rely on the barrierprovided by the dermis to regulate drug delivery rate.

[0010] Otitis media, inflammation of the middle ear, accounts for morevisits to pediatricians than any other illness. Otitis media isgenerally regarded as a complication of eustachian tube dysfunction. Thenormal eustachian tube is closed, except during swallowing, when itallows pressure equalization between the middle ear and nasopharynx.When it does not close properly, due to inflammation due to a cold, forexample, the eustachian tube can act as a conduit for movement ofbacteria into the middle ear from the nose. Gram-positivemicroorganisms, most prevalently S. pneumoniae and S. pyogenes,constitute the bacterial origin of otitis media. Furthermore, if theeustachian tubes are subsequently blocked so that negative pressuredevelops inside the middle ear, serum may leave the blood vessels in themiddle ear under hydrostatic pressure and accumulate there, a conditionknown as otitis media with effusion.

[0011] Treatment of otitis media involves observation and antibiotictherapy, and for infections that persist, surgical placement of eartubes. Antibiotic treatment of otitis media involves systemicadministration of antibiotics such as amoxicillin. Increasingly, the useof antibiotic therapy for treatment of this disease is coming intoquestion due to knowledge that widespread use of antibiotics allows forselection of resistant strains of bacteria. However, most physicianscontinue to prescribe antibiotics because it is difficult to predictwhich patients will get well without treatment and which will proceed tochronic otitis media and potentially fatal sequelae such as meningitis.

[0012] Installation of ear tubes is another treatment for otitis media.The tubes are grommets that are placed in the tympanic membrane so thata ventilation hole is maintained for fluid to escape from the middleear. Occasionally, ear tubes are removed by the surgeon after theinfection has cleared. More frequently, the ear tubes fall out of theear after the infection has resolved. In either case, the tympanicmembrane usually (in 60-70% of cases) heals with little or no hearingdysfunction. An unresolved problem with current ear tube designs is thatthey may fall out before the ear infection has resolved; this occurs inup to 25% of cases, increasing total cost of treating otitis media.

[0013] Suction tubes have been used in dentistry to help control andremove fluids from the oral cavity. Generally these tubes are prettysimple devices. Unfortunately, however, the tubes in use suffer fromsome drawbacks. First, they can be very noisy, causing the patient,dentist and/or assistant to become agitated or annoyed. Second, theygenerally suck fluid from only one point in the cavity. To remove fluidfrom other areas the tube must be manually repositioned. Moreover,positioning the tube into small openings or isolating individual teethor regions is precluded. Additionally, there have been reported cases ofcross contamination from patient to patient, caused from a malfunctionof the suction pump. Finally, the tube is prone to getting blocked bythe tissue.

[0014] From the foregoing, it will be appreciated that what is needed inthe art are articles having a built in capability to control ortransport fluids, especially biological fluids. In the case of surgicaldrape articles, there is a great need for articles that can control ortransport fluids emanating from a surgical site. In the case of medicaltreatment articles (e.g., wound dressings), there is a great need fordressings that keep the wound area at a preferred moisture level,articles that are capable of transporting fluid between the wound siteand a remote area, or are capable of delivering a medicament to a woundsite. It would be a further advancement in the art to provide sucharticles in a reliable and low cost manner. Such articles and methodsfor preparing the same are disclosed and claimed herein.

SUMMARY OF THE INVENTION

[0015] The present invention provides fluid control or transportarticles comprising at least one fluid control film component whichcomprises a sheet having at least one microstructure-bearing surfacewith one or more channels therein that permits, promotes, or facilitatescontrol or directional flow of a liquid. Medical treatment articlescontaining a fluid control film component are provided.

[0016] In one embodiment, this invention relates to novel surgicaldrapes that incorporate a fluid control film. The fluid control film maybe incorporated to transport a fluid to a remote site (e.g., facilitatewicking of a fluid away from an operating site and out of the way of thesurgeon), deliver a fluid to a site (e.g., facilitate delivery of amedicament or flushing solution to a surgery site), or absorb or containexcess wound exudate.

[0017] In another embodiment, this invention relates to novel wounddressings that incorporate at least one fluid control film. The fluidcontrol film may be incorporated to transport a fluid to a remote site,deliver a fluid to a site, disperse the fluid over an increased surfacearea to promote more rapid evaporation (e.g., through a high MVTR film),or absorb excess wound exudate. The dressings may be fabricated toaccommodate wounds of all types, including: bums, abrasions, surgicalwounds, lacerations, etc.

[0018] The topical wound dressing of one preferred embodiment transports(e.g., wicks) fluid off wounds by capillary action to a remote storagereservoir. This embodiment functions in an opposite manner toconventional wound dressings that place an absorbent over the wounditself. Dressings of this embodiment are preferably able to provide oneor more of the following benefits:

[0019] 1) wound moisture level optionally may be adjusted bymodification of the surface topography and/or surface energy of thefluid wick in combination with the MVTR of the dressing;

[0020] 2) the dressing is optionally and preferably transparent andallows visual inspection of the wound site; and

[0021] 3) an optional absorbent may be isolated or positioned remotefrom the wound site, thereby absorbing excess exudate while allowingdirect visualization of the wound. The absorbent is preferably coveredwith a permeable film, thus enabling the healthy tissue surrounding thewound not to be in contact with excess wound exudate.

[0022] The fluid transportation or “wicking” property may be provided byfluid control film incorporating a microreplicated pattern. The patternmay be provided in the backing or adhesive layer of a dressing, or by aseparate piece of film. The storage reservoir is preferably ahydrophilic fabric such as a woven, knit, or non-woven, a hydrocolloid,foam, or a gel system that is able to absorb large amounts of fluidexudate. Preferably a high MVTR transparent or translucent backing isused. Certain dressings may also be used to supply medicaments to thewound such as antimicrobials, antibiotics, growth factors, irrigationfluid, anesthetics/analgesics, and the like. Certain other dressings mayincorporate the optional medicaments directly into the adhesive, filmbacking, or microreplicated fluid transport wick.

[0023] In another embodiment, drug delivery dressings are provided. Thedelivery dressings incorporate fluid control film component tofacilitate delivery of a medicament to the skin.

[0024] In another embodiment, the present invention provides a noveltreatment for otitis media that utilizes novel tympanostomy wicks ortubes and/or a medicament (e.g., an antibacterial agent, preferably onethat is covalently attached to the tympanostomy article or placed in theinner ear by means of a syringe through the article itself). The novelwick or tube design utilizes microreplication to produce microchannelsthat transport fluid, e.g., by capillary action. Preferred designs alsoincorporate macrochannels to allow drainage of highly viscous fluid thatcannot be removed by capillary forces.

[0025] In another embodiment, dental suction devices are provided thatcomprise a fluid control film.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The invention may be more clearly understood by reference to thedrawings, wherein:

[0027]FIGS. 1a-1 g illustrate various medical dressings of the presentinvention;

[0028]FIGS. 2a-2 i illustrate additional medical dressings and medicalwound drains of the present invention;

[0029]FIGS. 3a-3 b illustrate a bottom view and cross-sectional view ofa medical dressing of the present invention;

[0030]FIGS. 3c-3 d illustrate additional medical dressings of thepresent invention;

[0031]FIG. 4a illustrates a branched wound drain of the presentinvention;

[0032]FIGS. 5a-5 c illustrate tympanostomy wicks of the presentinvention;

[0033]FIGS. 6a through 6 j are cross-sectional cutaway views ofillustrative embodiments of fluid control films of the presentinvention;

[0034]FIG. 7a is a perspective view of an active fluid transport devicein accordance with the present invention having a structured layercombined with a cap layer to provide multiple discrete channels that arein communication with a vacuum source;

[0035]FIG. 7b is an end view of a stack of structured layers that aredisposed upon one another so that bottom major surfaces of the layersclose off the structured surface of a lower layer to define multiplediscrete channels;

[0036]FIG. 7c is a perspective view of an aspirator in accordance withthe present invention utilizing a stack of multiple microstructuredlayers;

[0037]FIGS. 8a and 8 b are schematic diagrams used to illustrateinteraction of a liquid on a surface; and

[0038]FIGS. 9a and 9 b are top schematic views of structured layersillustrating alternative channel structures that may be used in a devicein accordance with the present invention.

[0039] These figures, which are idealized, are not to scale and areintended to be merely illustrative and non-limiting.

DEFINITIONS

[0040] Unless otherwise specified, the following terms should beconstrued in accordance with the following definitions:

[0041] Fluid Control Film (“FCF”) refers to a film or sheet or layerhaving at least one major surface comprising a microreplicated patterncapable of manipulating, guiding, containing, spontaneously wicking,transporting, or controlling, a fluid.

[0042] Fluid Transport Film (“FTF”) refers to a film or sheet or layerhaving at least one major surface comprising a microreplicated patterncapable of spontaneously wicking or transporting a fluid.

[0043] “Microreplication” means the production of a microstructuredsurface through a process where the structured surface features retainan individual feature fidelity during manufacture.

DETAILED DESCRIPTION OF THE INVENTION

[0044] The present invention relates to articles that incorporate afluid control film component. At the beginning of this section suitablefluid control films will be described generally. Descriptions ofillustrative articles incorporating these films will follow.

[0045] Suitable fluid control films for use in the present invention aredescribed in U.S. Pat. Nos. 5,514,120; 5,728,446, 6,080,243; and6,290,685. Preferred fluid control films of the invention are in theform of sheets or films rather than a mass of fibers. The channels offluid control films of the invention preferably provide more effectiveliquid flow than is achieved with webs, foam, or tows formed fromfibers. The walls of channels formed in fibers will exhibit relativelyrandom undulations and complex surfaces that interfere with flow ofliquid through the channels. In contrast, the channels in the presentinvention are precisely replicated from a predetermined pattern and forma series of individual open capillary channels that extend along a majorsurface. These microreplicated channels formed in sheets, films, ortubes are preferably uniform and regular along substantially eachchannel length and more preferably from channel to channel.

[0046] Certain of the fluid control films of the present invention arecapable of spontaneously and uniformly transporting liquids along theaxis of the film channels. Two general factors that influence theability of fluid control films to spontaneously transport liquids (e.g.,water, urine or vaginal secretions) are (i) the geometry or topographyof the surface (capillarity, shape of the channels) and (ii) the natureof the film surface (e.g., surface energy). To achieve the desiredamount of fluid transport capability the designer may adjust thestructure or topography of the fluid control film and/or adjust thesurface energy of the fluid control film surface. In order for a closedchannel wick made from a fluid control film to function it preferably issufficiently hydrophilic to allow the desired fluid to wet the surface.Generally, to facilitate spontaneous wicking in open channels, the fluidmust wet the surface of the fluid control film, and the contact angle beequal or less than 90 degrees minus one-half the notch angle.

[0047] The channels of fluid control films of the present invention canbe of any geometry that provides desired liquid transport, andpreferably one that is readily replicated.

[0048] The invention fluid control films can be formed from anythermoplastic materials suitable for casting, or embossing including,for example, polyolefins, polyesters, polyamides, poly(vinyl chloride),polyether esters, polyimides, polyesteramide, polyacrylates,polyvinylacetate, hydrolyzed derivatives of polyvinylacetate, etc.Polyolefins are preferred, particularly polyethylene or polypropylene,blends and/or copolymers thereof, and copolymers of propylene and/orethylene with minor proportions of other monomers, such as vinyl acetateor acrylates such as methyl and butylacrylate. Polyolefins are preferredbecause of their excellent physical properties, ease of processing, andtypically lower cost than other thermoplastic materials having similarcharacteristics. Polyolefins readily replicate the surface of a castingor embossing roll. They are tough, durable and hold their shape well,thus making such films easy to handle after the casting or embossingprocess. Hydrophilic polyurethanes are also preferred for their physicalproperties and inherently high surface energy. Alternatively, fluidcontrol films can be cast from thermosets (curable resin materials) suchas polyurethanes, acrylates, epoxies and silicones, and cured byexposure to heat or UV or E-beam radiation, or moisture. These materialsmay contain various additives including surface energy modifiers (suchas surfactants and hydrophilic polymers), plasticizers, antioxidants,pigments, release agents, antistatic agents and the like. Suitable fluidcontrol films also can be manufactured using pressure sensitive adhesivematerials. In some cases the channels may be formed using inorganicmaterials (e.g., glass, ceramics, or metals). Preferably, the fluidcontrol film substantially retains its geometry and surfacecharacteristics upon exposure to liquids. The fluid control film mayalso be treated to render the film biocompatible. For example, a heparincoating may be applied.

[0049] Generally, the susceptibility of a solid surface to be wet out bya liquid is characterized by the contact angle that the liquid makeswith the solid surface after being deposited on the horizontallydisposed surface and allowed to stabilize thereon. It is sometimesreferred to as the “static equilibrium contact angle”, sometimesreferred to herein merely as “contact angle”.

[0050] As shown in FIGS. 8a and 8 b, the contact angle Theta is theangle between a line tangent to the surface of a bead of liquid on asurface at its point of contact to the surface and the plane of thesurface. A bead of liquid whose tangent was perpendicular to the planeof the surface would have a contact angle of 90°. Typically, if thecontact angle is 90° or less, as shown in FIG. 8a, the solid surface isconsidered to be wet by the liquid. Surfaces on which drops of water oraqueous solutions exhibit a contact angle of less than 90° are commonlyreferred to as “hydrophilic”. As used herein, “hydrophilic” is used onlyto refer to the surface characteristics of a material, i.e., that it iswet by aqueous solutions, and does not express whether or not thematerial absorbs aqueous solutions. Accordingly, a material may bereferred to as hydrophilic whether or not a sheet of the material isimpermeable or permeable to aqueous solutions. Thus, hydrophilic filmsused in fluid control films of the invention may be formed from filmsprepared from resin materials that are inherently hydrophilic, such asfor example, poly(vinyl alcohol). Liquids that yield a contact angle ofnear zero on a surface are considered to completely wet out the surface.Polyolefins, however, are typically inherently hydrophobic, and thecontact angle of a polyolefin film, such as polyethylene orpolypropylene, with water is typically greater than 90°, such as shownin FIG. 8b.

[0051] Depending on the nature of the microreplicated film materialitself, and the nature of the fluid being transported, one may desire toadjust or modify the surface of the film in order to ensure sufficientcapillary forces of the article. For example, the surface of the fluidcontrol film may be modified in order to ensure it is sufficientlyhydrophilic. Body liquids that will come into contact with the fluidcontrol films of the present invention are aqueous. Thus, if such filmsare used as fluid control films of the invention, they generally must bemodified, e.g., by surface treatment, application of surface coatings oragents, or incorporation of selected agents, such that the surface isrendered hydrophilic so as to exhibit a contact angle of 90° or less,thereby enhancing the wetting and liquid transport properties of thefluid control film. Suitable methods of making the surface hydrophilicinclude: (i) incorporation of a surfactant; (ii) incorporation orsurface coating with a hydrophilic polymer; and (iii) treatment with ahydrophilic silane. Other methods are also envisioned.

[0052] The fluid control films of the invention may have a variety oftopographies. Preferred fluid control films are comprised of a pluralityof channels with V-shaped or rectangular cross-sections, andcombinations of these, as well as structures that have secondarychannels, i.e., channels within channels. For open channels, the desiredsurface energy of the microstructured surface of V-channeled fluidcontrol films is such that:

Theta≦(90°−Alpha/2),

[0053] wherein Theta is the contact angle of the liquid with the filmand Alpha (α) is the average included angle of the secondary V-channelnotches. (See, e.g., FIG. 6g).

[0054] Any suitable known method may be utilized to achieve ahydrophilic surface on fluid control films of the present invention.Surface treatments may be employed such as topical application of asurfactant, plasma treatment, vacuum deposition, polymerization ofhydrophilic monomers, grafting hydrophilic moieties onto the filmsurface, corona or flame treatment, etc. Alternatively, a surfactant orother suitable agent may be blended with the resin as an internaladditive at the time of film extrusion. It is typically preferred toincorporate a surfactant in the polymeric composition from which thefluid control film is made rather than rely upon topical application ofa surfactant coating. Topically applied coatings tend to fill in, i.e.,blunt, the notches of the channels, thereby interfering with the desiredliquid flow to which the invention is directed. An illustrative exampleof a surfactant that can be incorporated in polyethylene fluid controlfilms is TRITON™ X-100, an octylphenoxypolyethoxyethanol nonionicsurfactant, e.g., used at between about 0.1 and 0.5 weight percent. Anillustrative method for surface modification of the films of the presentinvention is the topical application of a 1 percent aqueous solution ofthe reaction product comprising 90 weight percent or more of:

[0055] wherein n=8 (97 percent), n=7 (3 percent), and 10 weight percentor less of:

[0056] wherein n=8 (97 percent), n=7 (3 percent). Preparation of suchagents is disclosed in U.S. Pat. No. 2,915,554 (Ahlbrecht et al.)

[0057] As discussed above, a surfactant or mixture of surfactants may beapplied to the surface of the fluid control film or impregnated into thearticle in order to adjust the properties of the fluid control film orarticle. For example, it may be desired to make the surface of the fluidcontrol film more hydrophilic than the film would be without such acomponent.

[0058] Preferred embodiments of the present invention retain the desiredfluid transport properties throughout the life of the product into whichthe fluid control film is incorporated. In order to ensure thesurfactant is available throughout the life of the fluid control filmthe surfactant preferably is available in sufficient quantity in thearticle throughout the life of the article or is immobilized at thesurface of the fluid control film. For example, a hydroxyl functionalsurfactant can be immobilized to a fluid control film by functionalizingthe surfactant with a di- or tri-alkoxy silane functional group. Thesurfactant could then be applied to the surface of the fluid controlfilm or impregnated into the article with the article subsequentlyexposed to moisture. The moisture would result in hydrolysis andsubsequent condensation to a polysiloxane. Hydroxy functionalsurfactants (especially 1,2 diol surfactants) may also be immobilized byassociation with borate ion. Suitable surfactants include anionic,cationic, and non-ionic surfactants, however, nonionic surfactants maybe preferred due to their relatively low irritation potential.Polyethoxylated and polyglucoside surfactants are particularly preferredincluding polyethoxylated alkyl, aralkyl, and alkenyl alcohols, ethyleneoxide and propylene oxide copolymers such as “Pluronic” and “Tetronic”,alkylpolyglucosides, polyglyceryl esters, and the like. Other suitablesurfactants are disclosed in U.S. Ser. No. 08/576,255.

[0059] As discussed above, a hydrophilic polymer or mixture of polymersmay be applied to the surface of the fluid control film or impregnatedinto the article in order to adjust the properties of the fluid controlfilm or article. In order to ensure the hydrophilic polymer is availablethroughout the life of the fluid control film the polymer preferably isavailable in sufficient quantity in the article throughout the life ofthe article or is immobilized at the surface of the fluid control film.Alternatively, a hydrophilic monomer may be added to the article andpolymerized in situ to form an interpenetrating polymer network. Forexample, a hydrophilic acrylate and initiator could be added andpolymerized by heat or actinic radiation.

[0060] Suitable hydrophilic polymers include: homo- and co-polymers ofethylene oxide; hydrophilic polymers incorporating vinyl unsaturatedmonomers such as vinylpyrrolidone, carboxylic acid, sulfonic acid, orphosphonic acid functional acrylates such as acrylic acid, hydroxyfunctional acrylates such as hydroxyethylacrylate, vinyl acetate and itshydrolyzed derivatives (e.g. polyvinylalcohol), acrylamides,polyethoxylated acrylates, and the like; hydrophilic modifiedcelluloses, as well as polysaccharides such as starch and modifiedstarches, dextran, and the like.

[0061] As discussed above, a hydrophilic silane or mixture of silanesmay be applied to the surface of the fluid control film or impregnatedinto the article in order to adjust the properties of the fluid controlfilm or article. Suitable silanes include the anionic silanes disclosedin U.S. Pat. No. 5,585,186 as well as non-ionic or cationic hydrophilicsilanes. Cationic silanes may be preferred in certain situations andhave the advantage that certain of these silanes are also believed tohave antimicrobial properties.

[0062] As previously mentioned, the channels of fluid control films ofthe present invention can be of any geometry that provides desiredliquid transport. In some embodiments, the fluid control film will haveprimary channels on only one major surface as shown in FIGS. 6a-6 c and6 g. In other embodiments, however, the fluid control film will haveprimary channels on both major surfaces, as shown in FIGS. 6i and 6 j.

[0063] As shown in FIG. 6a, channels 616 can be defined within the layer612 a in accordance with the illustrated embodiment by a series ofv-shaped sidewalls 617 and peaks 618. In some cases, the sidewalls 617and peaks 618 may extend entirely from one edge of the layer 612 toanother without alteration—although, in some applications, it may bedesirable to shorten the sidewalls 617 and thus extend the peaks 618only along a portion of the structured surface 613. That is, channels616 that are defined between peaks 618 may extend entirely from one edgeto another edge of the layer 612, or such channels 616 may only bedefined to extend over a portion of the layer 612. Channels that extendonly over a portion may begin at an edge of the layer 612, or they maybegin and end intermediately within the structured surface 613 of thelayer 612. The channels are defined in a predetermined, preferablyordered arrangement over a continuous surface of polymeric material.

[0064] As shown in FIG. 6b, channels 616′ have a wider flat valleybetween slightly flattened peaks 618′. Like the FIG. 6a embodiment, acap layer can be secured along one or more of the peaks 618′ to definediscrete channels 616′. In this case, bottom surfaces 630 extend betweenchannel sidewalls 631, whereas in the FIG. 6a embodiment, sidewalls 617connect together along lines.

[0065]FIG. 6c illustrates a configuration where wide channels 632 aredefined between peaks 618″, but instead of providing a flat surfacebetween channel sidewalls, a plurality of smaller peaks 633 are locatedbetween the sidewalls of the peaks 618″. These smaller peaks 633 thusdefine secondary channels 634 therebetween. Peaks 633 may or may notrise to the same level as peaks 618″, and as illustrated create a firstwide channel 632 including smaller channels 634 distributed therein. Thepeaks 618″ and 633 need not be evenly distributed with respect tothemselves or each other.

[0066]FIGS. 6d-6 j illustrate various alternative embodiments of thefluid control film of the present invention. Although FIGS. 6a-6 jillustrate elongated, linearly-configured channels, the channels may beprovided in other configurations. For example, the channels could havevarying cross-sectional widths along the channel length—that is, thechannels could diverge and/or converge along the length of the channel.The channel sidewalls could also be contoured rather than being straightin the direction of extension of the channel, or in the channel height.Generally, any channel configuration that can provide at least multiplediscrete channel portions that extend from a first point to a secondpoint within the fluid transport device are contemplated. The channelsmay be configured to remain discrete along their whole length ifdesired.

[0067] With reference to FIG. 6g, one preferred geometry is arectilinear primary channel 602 in a flat film 601. The primary channel602 has included secondary channels 603 which forms a multitude ofnotches 605. The notches 605 (or secondary channels 603, where thechannels are V-shaped and have substantially straight sidewalls) have anincluded angle of (i.e., angle Alpha) from about 10° to about 120°,preferably from about 10° to about 100°, and most preferably from about20° to about 95°. The notch included angle is generally the secant angletaken from the notch to a point 2 to 1000 microns from the notch on thesidewalls forming the notch, preferably the included angle is the secantangle taken at a point halfway up the secondary channel sidewalls. Ithas been observed that notches with narrower included angular widthsgenerally provide greater vertical wicking distance. However, if Alphais too narrow, the flow rate will become significantly lower. If Alphais too wide, the notch or secondary channel may fail to provide desiredwicking action. As Alpha gets narrower, the contact angle of the liquidneed not be as low, to get similar liquid transport, as the contactangle must be for notches or channels with higher angular widths.

[0068] The primary channel included angle is not critical except in thatit should not be so wide that the primary channel is ineffective inchanneling liquid. Generally, the primary channel maximum width is lessthan 3000 microns and preferably less than 1500 microns. The includedangle of a V-channel shaped primary channel will generally be from about10 degrees to 120 degrees, preferably 30 to 90 degrees. If the includedangle of the primary channel is too narrow, the primary channel may nothave sufficient width at its base so that it is capable of accommodatingan adequate number of secondary channels. Generally, it is preferredthat the included angle of the primary channel be greater than theincluded angle of the secondary channels so as to accommodate the two ormore secondary channels at the base of the primary channel. Generally,the secondary channels have an included angle at least 20 percentsmaller than the included angle of the primary channel (for V-shapedprimary channels).

[0069] With reference to FIGS. 6g and 6 i, the depth of the primarychannels (602, 622) (the height of the peaks or tops above the lowermostchannel notch), “d”, is substantially uniform, and is suitably fromabout 5 to about 3000 microns, typically from about 50 to about 3000microns, preferably from about 75 to about 1500 microns, and mostpreferably is from about 100 to about 1000 microns. It will beunderstood that in some embodiments films with channels (602, 622)having depths larger than the indicated ranges may be used. If thechannels are unduly deep, the overall thickness of the fluid controlfilm will be unnecessarily high and the film may tend to be stiffer thanis desired. The width of the primary channel at its base may besufficient to accommodate two or more secondary channels.

[0070]FIGS. 6i and 6 j illustrate fluid control films having primarychannels on both major surfaces. As shown in FIG. 6i, the primarychannels 622 may be laterally offset from one surface to the othersurface or may be aligned directly opposite each other as shown in FIG.6j. A fluid control film with offset channels as shown in FIG. 6iprovides a maximum amount of surface area for wicking while at the sametime using a minimum amount of material. In addition, a fluid controlfilm with offset channels can be made so as to feel softer, due to thereduced thickness and boardiness of the sheet, than a fluid control filmwith aligned channels as shown in FIG. 6j. As shown in FIG. 6j, fluidcontrol films 612 of the invention may have one or more holes orapertures 624 therein, which enable a portion of the liquid in contactwith the front surface of the fluid control film to be transported tothe back surface of the film, to improve liquid control. The aperturesneed not be aligned with the notch of a channel and do not need to be ofabout equal width as the channels. The surfaces of the fluid controlfilm within the apertures are preferably hydrophilic.

[0071] As illustrated in FIGS. 6g and 6 i, in each primary channel (602,622) are at least two secondary channels (603, 623) and at least twonotches (605, 625), the notch (605, 625) or notches of each secondarychannel (603, 623) is separated by a secondary peak (606, 626).Generally, each secondary channel will generally have only one notch,but a secondary channel will have two notches if the secondary channelis rectangular. The secondary peak (606, 626) for V-channel shapedsecondary channels is generally characterized by an included angle Pwhich is generally equal to (α¹+α²)/2 where α¹ and α² are the includedangles of the two adjacent V-channel shaped secondary channels (603,623), assuming that the two sidewalls forming each secondary channel aresymmetrical and not curved. Generally, the angle β would be from about10° to about 120°, preferably from about 10° to about 90°, and mostpreferably from about 20° to about 60°. The secondary peak could also beflat (in which case the included angle would theoretically be 0°) oreven curved, e.g., convex or concave, with no distinct top or includedangle. Preferably, there are at least three secondary channels (603,623) and/or at least three notches for each primary channel (602, 622),included any notches (605, 625) associated with the end channels(notches 608 or 609) as shown in FIG. 6g.

[0072] The depth of one of the secondary channels (603, 623) (the heightof the top of the secondary peaks 606 over the notches 605) is uniformover the length of the fluid control films, and is typically at least 5microns. The depth of the secondary channels (603, 623) is generally 0.5to 80 percent of the depth of the primary channels, preferably 5 to 50percent. The spacing of the notches (605, 625) on either side of a peak6 is also preferably uniform over the length of the fluid control film.Preferably the primary and/or secondary channel depth and width variesby less than 20 percent, preferably less than 10 percent for eachchannel over a given length of the fluid control film. Variation in thesecondary channel depth and shape above this range has a substantialadverse impact on the rate and uniformity of liquid transport along thefluid control film. Generally the primary and secondary channels arecontinuous and undisturbed.

[0073] Certain articles of the present invention comprise fluid controlfilm components that comprise layers of two or more films. Thesecomponents are particularly suitable for active fluid transport.

[0074] In FIG. 7a an active fluid transport device 710 is illustratedthat includes a layer 712 of polymeric material that has a structuredsurface 713 on one of its two major surfaces. The device 710 alsoincludes a source 714 for providing a potential to assist in moving afluid over the structured surface 713 of the active fluid transportdevice 710. Layer 712 also includes a body layer 715 from which thestructured surface 713 projects. Body layer 715 serves to supportstructured surface 713 to retain the individual structured featurestogether in layer 712.

[0075] Layer 712 may be comprised of flexible, semi-rigid, or rigidmaterial, which may be chosen depending on the particular application ofthe active fluid transport device 710. The layer 712 comprises apolymeric material because such materials can be accurately formed tocreate a microstructured surface 713. Substantial versatility isavailable because polymeric materials possess many different propertiessuitable for various needs. Polymeric materials may be chosen, forexample, based on flexibility, rigidity, permeability, etc. The use of apolymeric layer 712 also allows a structured surface to be consistentlymanufactured to produce a large number of and high density of channelsthat when capped form discrete fluid flow channels 716. Thus, a highlydistributed fluid transport system can be provided that is amenable tobeing manufactured at a high level of accuracy and economy. Thestructured polymeric surface 713 may be made from the same or differentmaterials of the body layer 715.

[0076] As shown in FIG. 7a, each of the channels 716 is opened at oneedge of the layer 712 to define channel inlets 719. Fluid can thus passthrough the inlets 719 guided by the channels 716 toward a further edgeof the layer 712 to a connector 720. The connector 720 preferably is influid communication with each of the channels 716 through outlets (notshown) and also is in fluid communication with the potential source 714.The connector 720 may be fashioned in a variety of forms but asillustrated in FIG. 7a, it includes a manifold 722. Manifold 722 isprovided with a plenum (not shown) that is defined internally thereinand which is in fluid communication with channels 716. The plenum maysimply comprise a chamber within the manifold 722 that is sealinglyconnected to at least a plurality of the channels 716. The manifold 722may be flexible, semi-rigid, or rigid, like the layer 712. A secondmanifold (not shown) also may be provided at the side of layer 712having inlets 720 so as to supply fluid to the channel 716, depending onthe particular application. The manifold may be formed usingmicroreplicated channels (e.g., converging channels).

[0077] In accordance with the invention, the connector may take onessentially any adaptation that enables the potential to be transferredfrom the source to the multiple channels. Although a manifold with aplenum and a tubing have been described, other connectors—such ascompression couplings, or seals and gaskets that fluidically join aconduit to the flow channels and permit the isolation or partition ofregions of higher and lower potential from the surroundingenvironment—are contemplated for use in this invention. The connectorcould also include capillary fibers, for example, less than 10 μm ininner diameter, each in fluid communication with an individual channelto allow individual fluids to flow discretely through separate channels.The connector could also be a molded chamber(s), a microstructured fluidconduit integrally or nonintegrally disposed relative to the discreteflow channels, or for example, a system or mechanism that allows thediscrete microstructured flow channels to be seated in a centrifuge orthat allows a flow stream such as a jet to be directed at channel inletsor outlets.

[0078] To close off or enclose at least part of the channels 716 at thepeaks 718, a cap layer 724 may be juxtaposed against the structuredsurface. Cap layer 724 thus closes at least a plurality of the channelsto create discrete flow channels 716 in a capillary module 725. Thecapillary module typically would have a thickness of 1 to 10 millimeters(mm), more typically 2 to 6 mm. Cap layer 724 may likewise sealinglyconnect to the manifold 722 so that plural discrete channels 716 provideactive fluid transport channels based upon the creation of a potentialdifference across the channels 716 from a first potential to a secondpotential. Cap layer 724 typically has a thickness of about 0.01 to 1mm, more typically 0.02 to 0.5 mm. If the channels of the invention arehermetically sealed then the flexible system of channels could generallywithstand high pressure without rupture, as a result of the hoopstrength of the small individual channels.

[0079] The cap layer 724 may be bonded to the peaks 718 of some or allof the structured surface 713 to enhance creation of discrete channels716. This can be done thermally or by using conventional adhesives thatare compatible with the cap layer material 724 and the polymericstructured layer 712. Formation of discrete channels 716 may beaccomplished through heat bonding, ultrasonic welding, compression, ormechanical engagement such as an interference fit. Bonds may be providedentirely along the peaks 718 to the cap layer 720, or the bonds may bespot welds or bonds that may be placed thereon in an ordered or randompattern.

[0080] Cap layer 724 preferably is made from a polymeric material suchas the polymers described below for the structured polymeric layer.Optionally, cap layer 724 may be a material such as a spunlaced,spunbond, blown microfiber or carded nonwoven. Polymers may be chosensuch that the cap layer can be secured to the structured surface 713without using an adhesive. Such a polymer could be chosen such that thecap layer becomes securely welded to the structured surface by applyingheat, for example, as from an ultrasonic welding operation.

[0081] The potential source may comprise essentially any means capableof establishing a potential difference along a plurality of the flowchannels 716 to encourage fluid movement from a first location to asecond location. The potential is sufficient to cause, or assist incausing, fluid flow through a plurality of flow channels 716, which isbased in part on the fluid characteristics of any particularapplication. As shown in FIG. 7a, the potential source 714 may comprisea vacuum generator (V) that is conventionally or otherwise connected toan optional collector receptacle 726. The collector receptacle 726 isfluidically connected to the manifold 722 by way of a conventionalflexible tube 728. Thus, fluid can be drawn from outside the capillarymodule 725 into the inlets 719, through channels 716, through manifold722, through tube 728, and into the collection receptacle 726. Thereceptacle 726 may advantageously be openable to empty its contents ormay be otherwise connected to conventional drainage systems.

[0082] In the case where the potential source 714 comprises a vacuumgenerator (V), the vacuum provided to the channels 716 via manifold 722can be sufficient to adequately seal the cap layer 724 to the peaks 718.That is, the vacuum itself will hold the cap layer 724 against peaks 718to form discrete channels 716. Preferably, each of the channels 716 thatare defined by the structured surface 713 is closed off by the cap layer724 so as to define a maximum number of discrete channels 716 capable ofindependently accommodating the potential. Fluid crossover betweenchannels 716 may be effectively minimized, and the potential providedfrom an external source can be more effectively and efficientlydistributed over the structured surface 713 of layer 712. When thepotential source 714 comprises a vacuum generator, manifold 722 need notbe sealed to channels 716 but may be simply placed adjacent an opensection of channels 716.

[0083] Connection between a microstructure-bearing surface, or capillarymodule, to a fluid conveyance or potential source can be achievedthrough a detachable or affixed manifold or manifolds as required.Multiple potential sources may also be employed depending on theparticular adaptation or application. Pressure differential is anefficient fluid motivation method or potential that may be used to driveflow across the microstructure-bearing surface(s). Pressure differentialcan be established readily through use of a pumping system and appliedeither in the form of positive or negative pressure.

[0084] Other potential sources 714 may be used in the present inventioninstead of or in conjunction with a vacuum generation device (V).Essentially any manner of causing or encouraging fluid flow through thechannels 716, particularly liquid flow, is contemplated for using thisinvention. The potential source is separate from the channeled structureand/or capillary module, or in other words is not intrinsic to thechanneled structure and/or capillary module. That is, the invention doesnot rely solely on the properties of the channeled structure to causefluid movement, for example, by capillary action. Examples of otherpotential sources include but are not limited to, vacuum pumps, vacuumaspirators, pressure pumps and pressure systems such as a fan, magnetohydrodynamic drives, acoustic flow systems, centrifugal spinning,hydrostatic heads, gravity, absorbents, and any other known or laterdeveloped fluid drive system utilizing the creation of a potentialdifference that causes or encourages fluid flow to at least to somedegree. Additionally, any applied field force that acts directly on thefluid such as a centrifugal force or magnetic field that causes fluid tomove within the channels of the invention may be considered a fluidmotive potential. Fluid may also be caused to flow through channels bythe action of a siphon where atmospheric pressure creates the potentialto move fluid in the channels.

[0085] Although the fluid transport device shown in FIG. 7a has astructured surface comprising multiple v-shaped peaks 718 (e.g., asshown in FIG. 6a), other configurations are contemplated.

[0086] As shown in FIG. 7b, a plurality of layers 712, each having amicrostructured surface 713 can be constructed to form a stack 750. Thisconstruction clearly multiplies the ability of the structure totransport fluid because each layer significantly increases flowcapacity. The layers may comprise different channel configurationsand/or number of channels, depending on a particular application.Furthermore, this type of stacked construction can be particularlysuitable for applications that are restricted in width and thereforerequire a relatively narrow fluid transport device from which a certainfluid transfer capacity is desired. Thus, a narrow device can be madehaving increased flow capacity.

[0087] A significant advantage of the stack 750 is that a second majorsurface 751 of layers 712 (the surface facing opposite the structuredsurface 713) can close off or cap the channels of an adjacent layer 712.In other words, separate cap layers are not required, although they maybe utilized, particularly to cover the exposed microstructured surface713 of the uppermost layer. Separate cap layers, however, could bedisposed over the second major surface 751 as an additional layer. Thematerial chosen for such an additional layer could be a polymericmaterial or otherwise depending on the particular application. Thelayers in the stack may be bonded to one another in any number ofconventional ways as described above, or they may simply be stacked uponone another such that the structural integrity of the stack canadequately define discrete flow channels. This ability may be enhanced,as described above, when a vacuum is utilized as the potential source.The second major surface 751 may be planar as shown, or it may be astructured surface similar to or different from surface 713.

[0088] Although the device shown in FIG. 7b includes a stack of 5structured surfaces 712, stacks may be configured that have othernumbers of stacks, for example, greater than 10 or even greater that 100structured layers, and may include tributary stacks that converge into alarger stack. For example, the five-layered stack shown in FIG. 7b couldbe divided into quarters, and each of the four tributary stacks (whichpossess channel inlets) could converge into the larger stackedconfiguration as shown in FIG. 7b which in turn could be attached to aconnector that communicates with a potential source. The stack couldinclude multiple connectors to allow multiple potential sources ofvarying potential to be attached to as subsets in the stack.

[0089] In FIG. 7c, a stacked construction, such as shown in FIG. 7b, isused in an aspirator 754. The aspirator 754 employs a stack 750 thatcomprises a plurality of layers 712, each having a microstructuredpolymeric surface 713 over one major surface thereof. The second majorsurface 751 of layers 712 acts as a cap layer, closing the channels 716of the adjacent sub layer 712 to create a stack or capillary module 750having a multiplicity of channel inlets 719 at the aspirator tip or end.The second major surface 751 may be polymeric, or it may be covered withother materials, e.g. metal foils, etc., as desired.

[0090] The capillary module 750 can be joined to a connector 755 thatincludes a tubing 756 and an adapter 758. The tubing 756 may be fastenedor otherwise joined to a potential source, such as a vacuum. The adapter758 joins the square cross-sectional capillary module 750 to the roundcross-sectional tubing 756 at the sealing connection region 759. Theadapter 758 may be conventionally, sealingly connected to tubing 756 andto the module 750 by adhesive or other bonding techniques. The stack ormodule 750 may or may not be further enclosed by a conduit or tubing.Alternatively, the tubing 756 and module 750 can be connected togetherby a section of shrinkable tubing into which ends of the tubing 756 andthe module 750 are inserted before shrinking. For example, heatshrinkable tubing or pre-stretched elastomeric tubing may be used. Thelayers 712, and thus the stack 750, may extend only a short distancefrom the adapter 758 so as to provide a relatively stiff aspirator end,or the layers 712 may extend further to make the aspirator 754 moreflexible. To provide a flexible and conformable aspirator end, theindividual layers 712 preferably are not bonded or otherwise secured toeach other over the whole surface of the layer, particularly at the end,to allow the layers 712 to slide or move relative to one another in thelongitudinal direction of the channels 712. This independent slidingmotion enables the tip to be bent around an axis normal to the flowchannels 716. When used in an aspirator, the module typically would beabout 1 to 10 cm in length. A stiff aspirator may be more applicable forinsertion into tight spaces, while flexibility may be desired so thatthe aspirator tip can be positioned at a more distal location whileconforming to a path to that location.

[0091] A sheath could also be applied over the capillary module 750 asdescribed. Dependent on the application, a porous or closed sheath couldbe placed around the stack. A porous sheath could be used forapplications where the sheath acts as a sieve or filter, and a closedsheath construction might be particularly suited to applications inendoscopic surgical procedures where liquid fluid delivery or extractionis needed.

[0092] The layers 712 may be assembled so that they are not adhered toone another, although they may connected as such if needed. Where thelayers 712 are not bonded together, the integrity of the stack 750,and/or a vacuum applied through tubing 756 can be relied upon toadequately define independent flow channels 716. In accordance with thepresent invention, the microstructured surface 713 of the layers 712define flow channels 716 that promote single-phase liquid flow. This isagain advantageous in that noise is reduced, which is particularlybeneficial in the medical field.

[0093] Another advantage of the aspirator 754, which comprises a stackof individual layers 712 that are unattached to one another, is that thestack 750 may be divided and even further subdivided into a plurality ofaspirator branches. That is, a part of the stack 750 may be directed toone particular location where a fluid is to be extracted, while anotherportion of the stack 750 is directed to another area where additionalfluid is extracted. Particularly, where the aspirator 754 relies on avacuum supplied through conduit or tubing 756 to remove fluid, anynumber of such divisions can be made whereby a plurality of individualdiscrete flow channels are provided within each branch. Tubing 756 couldalso be subdivided so that fluid from each particular branch orsubdivision in stack 750 is directed to its own respective conduit toallow appropriate fluid flow. Simultaneous irrigation and/or aspirationcould be achieved by such a device. That is, the separate conduits couldbe adopted to transport an irrigation fluid and an aspirated fluid. Thisfeature may be particularly beneficial for medical uses, includingdental uses, for aspirating more than one spot at a time.

[0094] A stacked module construction may include plural stacks arrangednext to one another. That is, a stack such as shown in FIG. 7b may bearranged adjacent to a similar or different stack. Then, they can becollected together by an adapter, such as shown in FIG. 7c, or they maybe individually attached to a fluid transfer tubing or the like.

[0095] Although the aspirator shown in FIG. 7c has essentially a linearprofile, it may be desirable in some embodiments to use an aspiratorthat has a different configuration. For example, the tubing 756 or theadapter 758 and/or the stack 750 may be curved or curvable to allow theaspirator to reach difficult areas or to allow the aspirator to supportitself. For example, if the aspirator shown in FIG. 7c could be used bya dentist to withdraw saliva and aqueous rinsing fluids that are presentin the patient's mouth. If the aspirator was hooked at its end, it couldrest on the patient's lip. The tubing 756 or adaptor 758 desirably isflexible to achieve such a curved configuration and may be made of adead soft material, or may contain such a material, to enable theaspirator to be temporarily bent into and retain such a curvedconfiguration. Such a device would be highly beneficial in that thedentist could more easily communicate with the patient and vice versawithout having to overcome the noise that is associated withconventional dental aspirators.

[0096] Other features or items may also be provided in front of theinlets 719 to the channels 716 for added functions. For example, a softfibrous end may be placed on the aspirator tip by adhering a mass ofcotton gauze or sponge-like material. This feature may be particularlyuseful for dental or other medical applications. Features could also beadded on the channel outlet side of the module to provide, for example,an irrigation function in conjunction with or in lieu of an aspirator.

[0097] Current aspirator technologies generally utilize relativelylarger diameter tubes to acquire and convey the aspirated liquid. It isnot uncommon for these tubes to have an inner diameter of one centimeteror larger. Unless the tubes are completely flooded during use, which isnot typical, the aspirator functions primarily in two-phase flow withair being the continuous phase that motivates the liquid movement in theflow system. This requires a relatively large air-to-liquid ratio, onein which the momentum of the flowing air is sufficient to carry theliquid. The required momentum of the air flow has many negative effectson the function of typical medical aspirators. These negative effectsmay include trauma to tissues contacted at the aspirator tip, highvolumetric air flows that can cause atomization of potentialbiohazardous liquids, increasing occupational exposure, and the generalnoise level of their operation.

[0098]FIGS. 9a and 9 b schematically illustrate channel configurationsin plan view that may define a structured surface in a fluid transportdevice of the invention. As shown, multiple discrete non-parallelconverging channels 936 provide for intermediate collection of fluid.These converging channels 936 connect to a single discrete channel 937.This minimizes the provision of outlet ports to one. As shown in FIG.9b, a central channel 938 connects to a plurality of channel branches939 that may be designed to cover a particular area for similar reasons.Again, generally any pattern is contemplated in accordance with thepresent invention as long as a plurality of discrete channels isprovided over a portion of the structured surface from a first point toa second point. Like the above embodiments, the patterned channels shownin FIGS. 9a and 9 b are preferably covered with a cap layer for furtherdefining discrete flow channels that allow the potential to beaccommodated along a particular channel essentially independent of itsneighboring channels.

[0099] As to any of the channels contemplated above and in accordancewith the present invention, such channels are defined within astructured layer by the structured surface of a first major surface ofthe layer. The channels in accordance with the present invention areconfigured to be discrete to allow any one channel to receive fluid fromthe ambient environment independently of the other channels. Themicrostructured size of each channel encourages single-phase flow offluid in bulk volumes. Without having air entrained in the liquid, noisegeneration is significantly reduced and less stress can be placed onliquids that are transported through the active fluid transport device.

[0100] The individual flow channels of the microstructured surfaces ofthe invention are substantially discrete. That is, fluid can movethrough the channels independent of fluid in adjacent channels. Thechannels independently accommodate the potential relative to one anotherto direct a fluid along or through a particular channel independent ofadjacent channels. Preferably, fluid that enters one flow channel doesnot, to any significant degree, enter an adjacent channel, althoughthere may be some diffusion between adjacent channels. It is importantto effectively maintain the discreteness of the micro-channels in orderto effectively transport the fluid and maintain advantages that suchchannels provide. Not all of the channels, however, may need to bediscrete for all embodiments. Some channels may be discrete while othersare not. Additionally, channel “discreteness” may be a temporaryphenomenon driven, for example, by fluctuating pressures.

[0101] The structured surface is a microstructured surface that definesdiscrete flow channels that have a minimum aspect ratio(length/hydraulic radius) of 10:1, in some embodiments exceedingapproximately 100:1, and in other embodiments at least about 1000:1. Atthe top end, the aspect ratio could be indefinitely high but generallywould be less than about 1,000,000:1. The hydraulic radius of a channelis no greater than about 300 micrometers. In many embodiments, it can beless than 100 micrometers, and may be less than 10 micrometers. Althoughsmaller is generally better for many applications (and the hydraulicradius could be submicron in size), the hydraulic radius typically wouldnot be less than 1 micrometers for most embodiments. As more fullydescribed below, channels defined within these parameters can provideefficient bulk fluid transport through an active fluid transport device.

[0102] The structured surface can also be provided with a very lowprofile. Thus, active fluid transport devices are contemplated where thestructured polymeric layer has a thickness of less than 5000micrometers, and possibly less than 1500 micrometers. To do this, thechannels may be defined by peaks that have a height of approximately 5to 1200 micrometers and that have a peak distance of about 10 to 2000micrometers.

[0103] Microstructured surfaces in accordance with the present inventionprovide flow systems in which the volume of the system is highlydistributed. That is, the fluid volume that passes through such flowsystems is distributed over a large area. Microstructure channel densityfrom about 10 per lineal cm and up to 1,000 per lineal cm (measuredacross the channels) provides for high fluid transport rates. Generally,when a common manifold is employed, each individual channel has anaspect ratio that is at least 400 percent greater, and more preferablyis at least 900 percent greater than a manifold that is disposed at thechannel inlets and outlets. This significant increase in aspect ratiodistributes the potential's effect to contribute to the noted benefitsof the invention.

[0104] Suitable fluid channels for use in the present invention may beof any suitable geometry but are generally rectangular (typically havingdepths of 50 μm to 3000 μm and widths of 50 μm to 3000 μm or “V” channelpatterns (typically having depths of about 50 μm to 3000 μm and heightsof 50 μm to 3000 μm) with an included angle of generally 20 to 120degrees and preferably about 45 degrees. The presently preferredstructure has a nested construction wherein the master channels are 200μm deep and repeat every 225 μm with three equally spaced channels inthe base each 40 μm deep. Compound channels are also possible and oftenpreferably such as rectangular channels that contain smaller rectangularor V channels within.

[0105] As mentioned previously, suitable fluid control film componentsof the present invention may be made through a process such asextrusion, injection molding, embossing, hot stamping, etc. In onetechnique, a substrate (e.g., a thermoplastic material) is deformed ormolded. This process is usually performed at an elevated temperature andperhaps under pressure. The substrate or material is preferably made toreplicate or approximately replicate the surface structure of a mastertool. Since this process produces relatively small structures and issometimes repeated many times over the process is referred to asmicroreplication. Suitable processes for microreplication are describedin U.S. Pat. No. 5,514,120.

[0106] In one embodiment, the present invention relates to wounddressings that incorporate fluid control film (e.g., microreplicatedwicks) to move fluid from one area and transfer it to another, e.g., bycapillary action. The presence of the fluid control film allows for adressing that can rapidly handle (e.g., absorb) large amounts of woundexudate while also optionally allowing visual observation of the wound.The fluid control film component of the present invention may serve tomove fluid such as wound exudate away from the wound to an absorbent, tosupply a fluid such as a medicament to a wound, or both.

[0107] Exemplary wound dressings of this invention are described andillustrate certain features of the present invention. In a preferredembodiment the wound dressing includes: (i) a fluid control film aspreviously discussed; (ii) an optional absorbent material; (iii) anoptional backing layer; and (iv) an optional adhesive. Each of thesecomponents is discussed in detail herein. The present invention alsoprovides assemblies of a dressing and a separate fluid control filmcomponent.

[0108] An optional absorbent may be used in articles of the presentinvention, e.g., to serve as a reservoir to collect fluid moved off oraway from the wound site. Preferably the absorbent is capable ofabsorbing fluid relatively quickly. More preferably, the absorbent iscapable of releasing the fluid (e.g., through evaporation through thedressing). The articles of this invention have the advantage of allowinga wide variety of product designs. Preferred designs can incorporateincreased surface area of the absorbent material, thereby allowing formanagement of more highly exuding wounds.

[0109] Suitable absorbent materials include fibrous textile typematerials, including woven, non-woven, knit, and stitch bonded materialsor absorbent foams. Alternatively, the absorbent can comprise anabsorbent polymer such as a hydrocolloid or hydrophilic polymer such asa supersorber. The hydrocolloid (e.g. starch, modified cellulose,gelatin or other protein, polysaccharide, etc) or supersorber (e.g.modified starch, acrylates, starch/acrylate copolymers, acrylamides andother vinyl polymers, etc) may be immobilized in a matrix such as ahydrophobic matrix of conventional hydrocolloid dressings or mayalternatively be part of a hydrophilic gel matrix (e.g. a UV or E-beamcured acrylate). The absorbent may also comprise both a fibrous textileand an absorbent polymer. The absorbent pad may optionally contain anantimicrobial agent.

[0110] Preferred dressings keep the absorbent pad off of the skin,thereby preventing damage to healthy tissue. This may be accomplishedusing porous films, for example, such as MICRODON, VISPORE, etc., whichmay be placed between the skin and the absorbent.

[0111] If desired, the dressing may be constructed using a two-piecefastener system such as those disclosed in U.S. Ser. No. 09/235,925.

[0112] Suitable backings for use in wound dressing articles of thepresent invention include conventional backings known in the artincluding non-woven and woven fibrous webs, knits, films, foams andother familiar backing materials. Preferred backings include thin (e.g.less than about 1.25 mm and preferably less than about 0.05 mm) andelastomeric backings. These types of backings help ensure conformabilityand high adhesion around the wound site. Preferred backing materialsinclude polyurethanes (e.g., ESTANE), polyether polyesters (e.g.,HYTREL), polyether amides (e.g., PEBAX) as well as polyolefins e.g.,ENGAGE). The backings also preferably provide a high moisture vaportransmission rate (MVTR) either through the film itself or by usingmicroscopic pores or perforations in the film. In the latter case, asuitable medical adhesive preferably covers the entire backing to ensurethat the backing does not allow influx of microbial contamination. Whenthin film backings are used wrinkle free application can be difficult.Any delivery method known to the art may be employed, including those ofU.S. Pat. Nos. 4,485,809, 4,600,001, and RE 33,727, as well as EPO No. 0051 935. The preferred method is a carrier delivery such as thatdisclosed in U.S. Pat. No. 5,738,642. In this embodiment, the backing issupported by a removable heat sealed carrier attached to the top face ofthe backing.

[0113] The carrier material used to supply the carriers for dressingsmanufactured according to the present invention is preferablysubstantially more rigid than the backing to prevent the backing fromwrinkling during application. The carrier material must also beheat-sealable to the backing, with or without the low adhesion coatingdescribed below, for the purpose of manufacturing the preferreddressings. In general, the preferred carrier materials can include, butare not limited to, polyethylene/vinyl acetate copolymer-coated papersand polyester films. One example of a preferred carrier material is apolyethylene/vinyl acetate copolymer-coated super calendared Kraft paper(1-90BKG-157 PE; Daubert Chemical Co.).

[0114] Suitable adhesive for use in wound dressing articles of thepresent invention include any adhesive that provides acceptable adhesionto skin and is acceptable for use on skin (e.g., the adhesive shouldpreferably be non-irritating and non-sensitizing). Preferred adhesivesare pressure sensitive and in certain embodiments preferably have arelatively high moisture vapor transmission rate to allow for moistureevaporation. Suitable pressure sensitive adhesives include those basedon acrylates, polyurethanes, KRATON and other block copolymers,silicones, rubber based adhesives (including natural rubber,polyisoprene, polyisobutylene, butyl rubber etc.) as well ascombinations of these adhesives. The adhesive component may containtackifiers, plasticizers, rheology modifiers as well as activecomponents such as an antimicrobial agent. It is anticipated thatremovable liners may be used to protect the adhesive surface prior touse. In addition, conventional frame components may be used if desired,e.g., to keep the dressing from wrinkling prior to application to thepatient.

[0115] The preferred pressure sensitive adhesives that can be used inthe adhesive composites of the present invention are the normaladhesives that are applied to the skin such as the acrylate copolymersdescribed in U.S. Pat. No. RE 24,906, particularly a 97:3 iso-octylacrylate:acrylamide copolymer. Also preferred is an 70:15:15 isooctylacrylate-ethyleneoxide acrylate:acrylic acid terpolymer, as described inU.S. Pat. No. 4,737,410 (Example 31). Other useful adhesives aredescribed in U.S. Pat. Nos. 3,389,827, 4,112,213, 4,310,509 and4,323,557. Inclusion of medicaments or antimicrobial agents in theadhesive is also contemplated, as described in U.S. Pat. Nos. 4,310,509and 4,323,557.

[0116] Liners which are suitable for use in the adhesive composites ofthe present invention can be made of kraft papers, polyethylene,polypropylene, polyester or composites of any of these materials. Theliners are preferably coated with release agents such as fluorochemicalsor silicones. For example, U.S. Pat. No. 4,472,480 describes low surfaceenergy perfluorochemical liners. The preferred liners are papers,polyolefin films, or polyester films coated with silicone releasematerials. Examples of commercially available silicone coated releasepapers are POLYSLIK™ silicone release papers available from James RiverCo., H.P. Smith Division (Bedford Park, Ill.) and silicone releasepapers supplied by Daubert Chemical Co. (Dixon, Ill.). The mostpreferred liner is 1-60BKG-157 paper liner available from Daubert, whichis a super calendared Kraft paper with a water-based silicone releasesurface.

[0117] Suitable fluid control film containing wound dressings aredesigned to utilize micro-grooves or channels (e.g., produced bymicroreplication) to transport fluid, e.g., by capillary action.Preferred designs may also incorporate pores or openings in the film toallow movement of fluid through the fluid control film, e.g., to theother side of the film and/or to an optional absorbent. One preferreddressing incorporates a fluid control film as a fluid wick that may beincorporated into the dressing by heat sealing or using adhesives intopreferred shapes and designs. Alternatively, the fluid wick can be partof the backing layer itself or may be provided as a structured adhesive.

[0118] The dressings of the present invention may take on a variety offorms. In one embodiment a preferred feature is that the dressing movesfluid from one portion of the dressing to an absorbent due to capillarychannels. Preferred dressings also keep the absorbent pad off of healthytissue and allow for the dressing to have a high MVTR (at least in onesection).

[0119] In order to function to remove wound exudate it is a preferredfeature that the fluid control film be in communication with both thefluid source (e.g. the wound) and the absorbent. Typically the fluidcontrol film will be placed directly above the wound site and transportfluid to the absorbent section of the dressing. The fluid control filmof the present invention may transport fluid in any direction suitableto move fluid between the wound site and a remote site on the dressing.For example, this may be along the length of a dressing (illustrated inFIGS. 1a and 1 b), the width of the dressing, may be radially patterned(FIG. 1c), or may incorporate combinations of these flow patterns.

[0120] Medicaments may be incorporated into articles of the presentinvention. Suitable medicaments include antimicrobials, antibiotics,analgesics, healing factors such as vitamins, growth factors, nutrientsand the like, as well as simple flushing with isotonic saline solutions.In preferred embodiments the wound dressings may serve both functions ofdelivering and removing fluid from the wound site.

[0121]FIG. 1a illustrates one embodiment of a wound dressing 30 of thepresent invention. Dressing 30 comprises film backing 32 with adhesivesurface; absorbent ring 34; and fluid control film 36. The channels inthe fluid control film 36 transport fluid from a covered wound site tothe absorbent ring 34. Alternatively, as shown in FIG. 1b two pieces ofabsorbent material (44 a and 44 b) may be utilized in place of absorbentring 34 of FIG. 1a. As shown in FIG. 1c, fluid control film 56 comprisesa plurality of channels radially extending toward a periphery.Alternatively, as shown in FIG. 1f, fluid control film 56 f comprises aplurality of channels in a cross-hatched pattern. In either case,absorbent ring 54 is positioned to absorb fluid transported via thefluid control film. Film backing 52 may be provided with an adhesivelayer to facilitate attachment of the dressing to the patient. Thedressings of the present invention may also incorporate fenestrations,slits, or other patterns to allow conformability to the patient or tofacilitate use of a auxiliary medical device such as an IV tube or wounddrain.

[0122]FIG. 1d is a bottom view of an alternative wound dressing 60 ofthe present invention. In this embodiment, fluid control film 66 isplaced against a porous dressing 62 on the side away from the patient.Holes, pores, or perforations through backing 62 communicate fluid tothe fluid control film surface. The fluid is thereby transported toabsorbent material 64.

[0123] Wound dressing 20 of FIG. 1g is designed to provide a high MVTR.In this embodiment, an adhesive coated thin film 22 is supported onliner 26 and by carrier frame 24. The adhesive coated thin film 22 hasat least one hole 27 extending through the adhesive and film. Preferablymultiple holes are employed and are distributed across the woundsurface. Sealed to the top side of thin film 22 (the side away from theskin) is a high MVTR fluid control film 28. Film 28 may be sealed tothin film 22 by any conventional means such as heat, ultrasonic welding,use of an adhesive, etc. Fluid control film 28 comprises microreplicatedchannels which serve to distribute excess wound exudate across film 28to increase surface area for evaporation. The microreplicated pattern isalso designed to prevent film 28 from bonding to film 22 as the woundexudate evaporates from the dressing. The dressing is applied by firstremoving liner 26 to expose the adhesive. Applying the dressing over thewound and subsequently removing carrier 24.

[0124] As stated previously the fluid control film structure (e.g., itsmicroreplicated pattern) may be incorporated into the wound dressing asa separate component, or as an integral part of the dressing (e.g., inpart or all of the film backing or into the adhesive layer of thedressing).

[0125] When the fluid control film is a separate piece it is usuallypresent as a piece of film preferably produced either by a filmextrusion or hot stamping process. It should be understood that thispattern may be made off-line or may be made integral with the convertingoperation. The film may be produced with one or both major surfaceshaving a microreplicated pattern.

[0126] It is preferred to maintain the MVTR of the dressing quite highto also allow for evaporation of the exudate. This feature canfacilitate prolonged wearing of the dressing. One preferred method ofachieving high MVTR is to incorporate thin dressings (e.g., at least aportion of its total area is thin).

[0127] The fluid control film may also be part of the backing itself. Aswith the film the microreplicated pattern may be manufactured into thebacking off-line as part of an extrusion, embossing, or other process orit may be incorporated into the film as part of the converting process.The backing may incorporate the pattern on one or both surfaces asdescribed above for the film. It is presently believed that the fluidcontrol film structure is preferably incorporated into the film backingitself wherein the film contacts the wound fluid directly and transportsthe fluid to a remote absorbent. This design is preferred since it bothprovides a very high MVTR product and lower cost manufacturing since noadditional fluid wick component is required. In this case where the filmhas the fluid control film capability it is understood that the adhesivelayer may be discontinuous to allow fluid to enter the structure on thefilm backing. Preferably no adhesive is present on the film wickstructure immediately above the wound site since this will provide forthe most efficient fluid wick capability and the highest MVTR. If theadhesive layer is sufficiently hydrophilic and allows moisture passagerapidly, it may be a continuous layer such as is shown in FIG. 2h.

[0128] The fluid wick may also be incorporated into an adhesive layer.In this case the adhesive must either be supported by a microreplicatedliner having the mirror image of the fluid wick pattern or the adhesivemust have sufficient yield stress and/or creep resistance to preventflow and loss of the pattern during storage. Increase in yield stress ismost conveniently accomplished by slightly crosslinking the adhesive(e.g., using covalent and/or ionic crosslinks or by providing sufficienthydrogen bonding).

[0129]FIG. 2a illustrates a simple wound dressing 70 of the presentinvention having a film backing 72 with adhesive surface; absorbent pad74 at one end of the dressing; and fluid control film 76. The channelsin the fluid control film 76 transport fluid from a covered wound siteto the absorbent 74. This design illustrates how dressings can beconstructed where the absorbent pad is remote from the tissue in thewound site. The backing 72 may extend beyond the absorbent pad on allsides of the pad or the pad may completely cover the backing at one endof the dressing (as shown in FIG. 2b).

[0130]FIG. 2c illustrates a dressing 80 of the present invention thatcomprises a film backing 82 with adhesive surface; and fluid controlfilm 81. The channels in the fluid control film 81 transport fluid froma covered wound site to a remote site.

[0131]FIG. 2d illustrates a perspective view of a combined wounddressing and drain of the present invention. FIG. 2e illustrates across-sectional view of the dressing 90, taken along line 2 e-2 e. Inthis embodiment the dressing 90 comprises a backing 91 having anadhesive surface 93; an absorbent pad 94; and a fluid control filmcomponent 96 that transports fluid between a wound site and theabsorbent pad 94. The fluid control film component of this embodimentmay be bent away from the dressing and placed into a wound. In thismanner the fluid control film component may be better able to drain thewound of excess fluid. If desired, the fluid control film could beextended past the edge of the dressing and the absorbent pad placedremote from the dressing. Also, in place of an absorbent pad it iscontemplated that a suction device could be used to transport fluids toor from the wound site. FIG. 2f illustrates an alternativecross-sectional view of the dressing of FIG. 2d. In this embodiment thedressing 90 comprises a backing 91 having an adhesive surface 93; anabsorbent pad 94; and a fluid control film component 96 that transportsfluid between a wound site and the absorbent pad 94. In this embodimentthe absorbent pad is placed between one end of the fluid control film 96and the adhesive layer 93 of the dressing. In this embodiment, fluidcontrol film 96 may be a separate component inserted in or applied to awound surface, with dressing 90 subsequently applied.

[0132]FIG. 2g illustrates a bottom view of a perfusion bandage 84 of thepresent invention. In this embodiment fluid is provided under a dressing85 from a reservoir 86 (shown schematically) using a fluid control filmcomponent 87. The fluid provided to the wound site from the reservoirmay optionally contain a medicament (e.g., an antibiotic, antiseptic,steroid, growth factor, and the like). Excess fluid and wound exudateare optionally removed from the wound site using fluid control film 87into a remote storage container 88 (e.g., an absorbent (such as a pad,gel, foam, and the like) or a reservoir of a suction device).

[0133]FIG. 2h illustrates yet a further alternative article 200 of thepresent invention. In this embodiment an adhesive layer 202 liesadjacent a portion of a fluid control film component 206. The channelsof the fluid control film are effectively closed by the adhesive layer202 but not occluded. An optional absorbent pad 204 may be placedadjacent a remote end of the fluid control film component.Alternatively, the remote end of the fluid control film component may beconnected to a fluid source or suction device.

[0134]FIG. 2i illustrates a side view of a wound drain dressing of thepresent invention. The wound drain dressing 220 is shown with aconventional medical dressing 222 having backing 224 and adhesive layer223. This dressing is adapted to be attached via adhesive layer 223 tothe skin of a patient adjacent a wound site. An absorbent pad 225 isplaced adjacent the backing of dressing 222 and held in place using anysuitable means. In fluid communication with the absorbent pad is alength of fluid control film 226. The remote end 221 of the fluidcontrol film is capable of being placed into a wound. Fluids are thentransported between the wound and the pad 225. Tape 227 (having adhesivelayer 228 and backing 229) may be utilized to secure fluid control film226 and pad 225 to the dressing 222. This is only one suitable method ofsecuring the components together. Adhesives, sonic welding techniques,etc. may be utilized in place of tape 227 if desired.

[0135] Wound drain 240 of FIG. 2j is comprised of a tubular piece offluid transport film where in the microreplicated channels are on theinside of the tube. The tube may be formed from two pieces of fluidtransport film sealed at the edges, as an extruded tube or in any othersuitable manner. On the wound contact end 241 of the wound drain 240,part of the tube has been removed up to point 248 to exposemicroreplicated channels 242. In use, these channels are placed in fluidcontact with the wound. Extending from edge 248 to edge 249 on one sideof the wound drain 240 or around the entire circumference is coated apressure sensitive adhesive 244. Adhesive 244 would be then covered witha removable protective release liner.

[0136] The wound drain 240 is applied by removing the liner and adheringadhesive section 244 to the wound site with channels 242 over the woundwith at least a portion of channels 242 exposed to wound exudate. Adressing may then optionally be placed over the entire wound area andover the wound drain 240 from end 241 up to at least edge 249. Opening246 can be placed in fluid communication with a vacuum source oradsorbent. For example, an absorbent could be placed inside the drain ator near opening 246.

[0137] As previously mentioned, the fluid control film component of thepresent invention may comprise multiple layers of microreplicated filmin various configurations, including but not limited to: simple stacksof the fluid control film, laminated layers of the fluid control filmforming closed capillaries between layers, as well as tubularconfigurations.

[0138] Certain multiple layer or tubular configurations of fluid controlfilm can be used as components to transparent dressings such asapertured transparent dressings. For example, a tubular fluid wick couldbe formed with an absorbent core along part or all of a length that isinserted into an aperture or under the end of a dressing such as anadhesive coated transparent dressing.

[0139]FIG. 3a and FIG. 3b illustrate bottom and cross-sectional views ofa wound dressing 100 of the present invention. The dressing 100 includesmedical dressing 102 (having backing 105 and adhesive layer 103); atleast one aperture 101; and a fluid control film wick member 108comprising a plurality of fluid control film (106 a and 106 b shown,though more layers could be used) and one or more absorbent pads 104.Fluid from the wound site leaves the site through aperture 101 and istransported by the wick member 108 to the absorbent.

[0140] In preferred embodiments, the fluid control film wick member liesflat and is sealed to the aperture by having the top layer extend overthe opening as shown. Alternatively, a separate absorbent drain tubecould be used by optionally adhesive coating the tip to allow placementfollowed by securing such as beneath a standard adhesive coateddressing.

[0141] In yet another embodiment, a fluid control film component couldbe used as a post surgical drain tube, wherein the microreplicatedchannels are on the interior of the tube, to allow for removal of woundexudate. In this application the drain tube may not be in communicationwith an absorbent but is rather hooked up to a vacuum source such as avacuum pump or “HEMAVAC”. Tubular drains may be formed directly byextrusion or from a film that is rolled into a tube and sealed or fromtwo pieces of film optionally sealed at the edges. These drain tubeshave certain advantages over a standard extruded tubular drain.

[0142] Preferred fluid control film drains of the present invention havelow profile, producing less pain while employed and enabling the drainto be removed with less pain. In this design the structured fluidcontrol film is designed to prevent occlusion as vacuum is applied. Morepreferred fluid control film drains can also remove gross fluids as doneby current drain tubes while also removing fluid by capillary action.Certain embodiments may further comprise larger structures that serve tokeep the tubular drain open to the desired degree. Finally, mostpreferred fluid control film drains may be made with linear fluidtransport structures that have the capability of being ripped or tornlinearly down the channel such that the end of a single drain tube couldbe split into multiple drains. In this manner, a single fluid controlfilm drain could be used to replace multiple conventional drains.

[0143] As previously mentioned, in the wound dressing or wound drainembodiments of the present invention the microreplicated fluid transportchannels may be present in the backing of the dressing, in the adhesivecoating, or as a separate added insert.

[0144] As illustrated in FIG. 3c, a dressing 140 comprises a pluralityof microreplicated channels in the adhesive layer of sheet 142.Absorbent regions (144 a, 144 b) may be used. Preferably, the absorbentregions are separated from the skin, e.g., using a layer of a suitableprotective material such as MICRODON or DELNET.

[0145] In this embodiment excess wound exudate is transported off thewound (or an active agent could be delivered to a wound) by amicroreplicated open capillary design formed into the adhesive itself.The adhesive is preferably non-flowable under zero shear, i.e. at rest,so that the pattern will remain intact during storage and while in use.This may be accomplished by crosslinking the adhesive through covalentbonds, ionic bonds, or through hydrogen bonding. For example, this maybe achieved by crosslinking an acrylate adhesive with light, UV, heat,gamma or electron beam. Suitable adhesives of this type are disclosed inU.S. Pat. Nos. 5,225,473; 5,468,821 and 5,853,750. Alternatively, theadhesive can be a crosslinked polyurethane such as that disclosed inU.S. Pat. No. 5,591,820. An example, of suitable adhesives that can becrosslinked by hydrogen bonding in those disclosed in U.S. Pat. No.4,871,812. The microreplicated fluid transport capillaries may bearranged in either or both major direction of the dressing or may bedirected radially. Preferably the direction of the channels is acrossthe dressing rather than down the dressing. This allows placement of theadhesive pads in a rotary converting operation without waste. Also,transport distance is minimized in this manner. Finally, the ends of thedressing are sealed, i.e. fluid cannot be wicked into the wound. Incertain instances where it may be desirable to administer therapeuticagents to the wound the capillary channels may be turned 90 degrees suchthat they would run the length of the dressing. In this case, it may benecessary to seal the edges of the dressing with tape to preventcontamination from entering the wound from the exposed edges.

[0146] By making the capillary channels in the adhesive itself the costof the dressing is minimized and the MVTR is maximized.

[0147] Alternatively, as illustrated in FIG. 3d, a dressing 160comprises a plurality of microreplicated channels 146 in the backinglayer of sheet 162. Absorbent regions (164 a, 164 b) may be used and maybe separated from the skin during use by a suitable protective material(e.g., MICRODON or DELNET). Adhesive strips (163 a, 163 b) may be laiddown on the lateral edges of the dressing. To form a complete sealaround the entire dressing periphery, additional adhesive strips may beplaced down across the other two edges of the dressing. Alternatively,the user could seal those edges with adhesive tape. The fluid transportcapillaries travel at least up to and preferably over the absorbent toensure the fluid is absorbed efficiently by the absorbent. To facilitatea fully automated manufacturing operation, the entire surface of thebacking may be microreplicated, followed by a thermal nip applied onlyto the longitudinal edges immediately beneath and prior to placement ofthe adhesive. In this manner, the adhesive contact area is maximized.Alternatively, the adhesive could be simply placed over and occlude themicroreplicated channels on the periphery of the dressing.

[0148]FIG. 4a is a perspective view of a fluid control film drain 120 ofthe present invention. The drain 120 is shown partially inserted into acavity 125 of a body surface 124. The inserted end of the fluid controlfilm drain has been split into three branches 126 a-c each of which iscapable of transporting fluid by capillary action. Preferred drains ofthis type have channels that run the length of the drain and areconfigured to facilitate longitudinal tearing. In this manner, the drainmay be easily split to drain multiple areas. The other end of the fluidcontrol film tube may be attached to a vacuum source or in communicationwith an absorbent material. In this embodiment, the drain tube is heldin place using, for example, a suture or skin staple placed directly inthe drain or in a cuff around the drain as is common with conventionalwound drains. Alternatively, an adhesive coated dressing or sealant maybe used.

[0149] In another embodiment, the present invention provides a noveltreatment for otitis media that utilizes novel tympanostomy wicks ortubes and/or a medicament (e.g., an antibacterial that can be coated on,incorporated in, or covalently attached to the article or placed in theinner ear by means of a syringe through the article itself). The novelwick or tube design utilizes microreplication to produce microchannelsthat transport fluid, e.g., by capillary action. Preferred designs alsoincorporate macrochannels to allow drainage of highly viscous fluid thatcannot be removed by capillary forces. Suitable tympanostomy wicks ortubes incorporate a fluid control film as a fluid wick. Suitable filmsmay be fabricated (e.g., by heat sealing or using adhesives) intopreferred shapes and designs. Alternatively, a tube may be injectionmolded with microreplicated channels on the device itself. Furthermore,with an injection molded article the channels may be designed to havethe fluid preferentially move in one direction, e.g. out of the ear, byhaving the channels tapered appropriately. The surface of the channelsmay be modified to make them hydrophilic as discussed herein.

[0150] A further preferred aspect of the design is the collapsibleumbrella-like end of the wick that prevents the wick from dislodgingfrom the ear until the physician wishes it removed. As illustrated inFIG. 5a, the tympanostomy wick 180 comprises a strip of fluid controlfilm component 182 and optional stop or collar 184 which serves toprevent the tube from going into the middle ear too far duringinsertion. As mentioned, the film 182 may be bent or folded 186 ifdesired. Also, fluid control film component 182 may comprise a singlelayer of fluid control film having channels on one of both surfaces) ormay comprise a plurality of films in a stack. FIG. 5b illustrates atympanostomy wick of the present invention comprising two strips offluid control film component (192, 193), and optional stop or collar194. Components 192, 193 may individually comprise one or more fluidcontrol films. In this embodiment, components 192, 193 are bent awayfrom each other at one end of the wick. The umbrella end is flexibleenough to allow removal by the physician by forceps alone. It isanticipated that the function of stop (184, 194) may be achieved usingmolded projections or microstructure on the film. For example, as shownin FIG. 5c, a series of angled projections (195, 197) may be moldedalong the surface of the film to prevent the wick from dislodging fromthe ear. The angled projections may be angled toward an insertion pointof the wick (199), thus allowing easy insertion of the wick to thedesired depth and retention of the wick in both directions.

[0151] The fluid control film (wicks or tubes) optionally may beutilized to deliver a medicament to the inner ear. Suitable medicamentsfor this treatment include traditional antiseptics and antibiotics.

[0152] All references and publications cited herein are expresslyincorporated herein by reference, in their entirely, into thisdisclosure. Particular embodiments of this invention will be discussedin detail in the examples below and reference has been made to possiblevariations to the particular embodiments that are within the scope ofthe invention. There are a variety of alternative techniques andprocedures available to those skilled in the art that would similarlypermit one to successfully practice the intended invention.

What is claimed is:
 1. A medical treatment article, comprising: at leastone fluid control film component having at least onemicrostructure-bearing surface with a plurality of channels therein thatpermit directional control of a liquid.
 2. The article of claim 1,wherein the article is selected from the group consisting of wounddressings, wound drains, tympanostomy fluid wicks, intravenous accesssite dressings, drug delivery dressings, surgical drape, and sweatcollection patches.
 3. The article of claim 1, wherein themicrostructure-bearing surface is hydrophilic.
 4. The article of claim1, wherein the article further comprises an absorbent pad positioned influid communication with the fluid control film.
 5. The article of claim1, wherein the channels have a cross-sectional geometry selected fromthe group consisting of V-shaped channels, rectangular-shaped channelsor combination V- and rectangular-shaped channels.
 6. The article ofclaim 1, wherein the fluid control film comprises a plurality of primarychannels having at least two secondary channels, each of the secondarychannels forming at least one notch.
 7. The article of claim 6, whereinthe primary channels have a depth of from 50 to 3000 microns and thedepth of the secondary channels is from 5 to 50 percent of the depth ofthe primary channels.
 8. The article of claim 1, wherein the channel hasan included angle between about 10 degrees and 120 degrees.
 9. Thearticle of claim 1, wherein the channels are between about 5 and 3000microns deep.
 10. The article of claim 1, wherein the channels arebetween about 50 and 1500 microns deep.
 11. The article of claim 1,wherein the channels are between about 100 and 1000 microns deep. 12.The article of claim 3, wherein the channel is open and has an includedangle Alpha, Alpha being between about 10 and 120 degrees, and thehydrophilic surface has a contact angle with water of Theta, Theta beingequal to or less than the sum of 90 degrees minus one-half Alpha. 13.The article of claim 1, wherein the channels are substantially parallelthroughout their length.
 14. The article of claim 1, wherein thechannels comprise a thermoplastic material selected from the groupconsisting of polyolefins, polyesters, polyamides, poly(vinyl chloride),polyether esters, polyimides, polyesteramide, polyacrylates,polyvinylacetate, hydrolyzed derivatives of polyvinylacetate andcombinations thereof.
 15. The article of claim 1, wherein the channelscomprise a thermoset material selected from the group consisting ofpolyurethanes, acrylates, epoxies and silicones.
 16. The article ofclaim 1, wherein the channels comprise a pressure sensitive adhesivematerial.
 17. The article of claim 1, wherein the channels are openalong at least a major portion of their length.
 18. The article of claim1, wherein the channels are closed along at least a major portion oftheir length.
 19. The article of claim 1, wherein the article is a wounddressing and the fluid control film is adapted to be positioned in fluidcommunication with a wound.
 20. The article of claim 1, wherein thearticle is a wound dressing further comprising one or more absorbentpads positioned in fluid communication with the fluid control film. 21.The article of claim 20, wherein the fluid control film comprises aseparate piece of film.
 22. The article of claim 20, wherein thechannels are formed within an adhesive layer of the dressing.
 23. Thearticle of claim 20, wherein the channels are formed within a backinglayer of the dressing.
 24. The article of claim 1, wherein the articleis a combined wound dressing and wound drain, and the fluid control filmis adapted to be inserted into a wound.
 25. The article of claim 1,wherein the article is a wound dressing and the fluid control film isadapted to supply a medicament to a wound site.
 26. The article of claim1, wherein the article is a wound drain.
 27. The article of claim 26,wherein the fluid control film is branched at one end.
 28. The articleof claim 26, wherein the fluid control film is adapted to a vacuumgenerator at one end.
 29. The article of claim 26, wherein the drainfurther comprises one or more absorbent pads positioned in fluidcommunication with the fluid control film.
 30. The article of claim 1,wherein the article is a tympanostomy wick.
 31. The article of claim 30,wherein the wick comprises at least two pieces of fluid control film andthe film is bent at one end to form an umbrella end.
 32. The article ofclaim 1, wherein the article is a surgical drape comprising a sheet ofdrape material and the fluid control film component is positioned todirect fluid toward a collection device selected from the groupconsisting of absorbent pads and collection pouches.
 33. The article ofclaim 32, wherein at least a portion of the drape is coated with anadhesive.
 34. The article of claim 1, wherein the fluid control filmcontains at least one aperture therein.
 35. The article of claim 1,wherein the fluid control film is translucent.